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Date: Wed, 16 Sep 2009 01:23:26 +0100 (BST) From: Hugh Dickins <hugh.dickins@...cali.co.uk> To: Ingo Molnar <mingo@...e.hu> cc: Yinghai Lu <yinghai@...nel.org>, Hugh Dickins <hugh.dickins@...cali.co.uk>, Linus Torvalds <torvalds@...ux-foundation.org>, Zachary Amsden <zach@...are.com>, "H. Peter Anvin" <hpa@...or.com>, Xiao Guangrong <xiaooguangrong@...fujitsu.com>, Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org Subject: Re: linux-next: reservetop fix disables mem= On Mon, 24 Aug 2009, Ingo Molnar wrote: > * Yinghai Lu <yinghai@...nel.org> wrote: > > Hugh Dickins wrote: > > > I find the "mem=" boot parameter disabled in today's linux-next: > > > reverting the tip commit below fixes that. > > > > > > Hugh > > > > > > From: Xiao Guangrong <xiaoguangrong@...fujitsu.com> > > > Date: Thu, 20 Aug 2009 12:23:11 +0000 (+0800) > > > Subject: x86: Fix system crash when loading with "reservetop" parameter > > > X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fmingo%2Flinux-2.6-x86.git;a=commitdiff_plain;h=8126dec32738421afa362114337331337b4be17f > > > > > > x86: Fix system crash when loading with "reservetop" parameter > > > > > > The system will die if the kernel is booted with "reservetop" > > > parameter, in present code, parse "reservetop" parameter after > > > early_ioremap_init(), and some function still use > > > early_ioremap() after it. > > > > > > The problem is, "reservetop" parameter can modify > > > 'FIXADDR_TOP', then the virtual address got by early_ioremap() > > > is base on old 'FIXADDR_TOP', but the page mapping is base on > > > new 'FIXADDR_TOP', it will occur page fault, and the IDT is not > > > prepare yet, so, the system is dead. > > > > > > So, put parse_early_param() in the front of > > > early_ioremap_init() in this patch. > > > > > > Signed-off-by: Xiao Guangrong <xiaoguangrong@...fujitsu.com> > > > Cc: yinghai@...nel.org > > > Cc: Andrew Morton <akpm@...ux-foundation.org> > > > LKML-Reference: <4A8D402F.4080805@...fujitsu.com> > > > Signed-off-by: Ingo Molnar <mingo@...e.hu> > > > --- > > > > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > > > index 63f32d2..02643cc 100644 > > > --- a/arch/x86/kernel/setup.c > > > +++ b/arch/x86/kernel/setup.c > > > @@ -711,6 +711,11 @@ void __init setup_arch(char **cmdline_p) > > > printk(KERN_INFO "Command line: %s\n", boot_command_line); > > > #endif > > > > > > + strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > > > + *cmdline_p = command_line; > > > + > > > + parse_early_param(); > > > + > > > /* VMI may relocate the fixmap; do this before touching ioremap area */ > > > vmi_init(); > > > > > > @@ -793,11 +798,6 @@ void __init setup_arch(char **cmdline_p) > > > #endif > > > #endif > > > > > > - strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); > > > - *cmdline_p = command_line; > > > - > > > - parse_early_param(); > > > - > > > #ifdef CONFIG_X86_64 > > > check_efer(); > > > #endif > > > > yes, that patch will break other built-in command too. > > > > need drop that patch. > > done. Was nervous about the patch already: Somehow it seems to have undropped itself, so mem= stopped working again in recent mmotm/linux-next; and it looks like today the undropped patch has made its way to Linus - I've not built current git to check, but I think you'll find mem= is now broken there. Hugh > > http://lkml.org/lkml/2009/8/21/127 > > > also the problem was caused by vmi patch, and that commit should > > be reverted. > > > > commit ae8d04e2ecbb233926860e9ce145eac19c7835dc > > Author: Zachary Amsden <zach@...are.com> > > Date: Sat Dec 13 12:36:58 2008 -0800 > > > > x86 Fix VMI crash on boot in 2.6.28-rc8 > > > > VMI initialiation can relocate the fixmap, causing early_ioremap to > > malfunction if it is initialized before the relocation. To fix this, > > VMI activation is split into two phases; the detection, which must > > happen before setting up ioremap, and the activation, which must happen > > after parsing early boot parameters. > > > > This fixes a crash on boot when VMI is enabled under VMware. > > > > Signed-off-by: Zachary Amsden <zach@...are.com> > > Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org> > > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > > index 9d5674f..bdec76e 100644 > > --- a/arch/x86/kernel/setup.c > > +++ b/arch/x86/kernel/setup.c > > @@ -794,6 +794,9 @@ void __init setup_arch(char **cmdline_p) > > printk(KERN_INFO "Command line: %s\n", boot_command_line); > > #endif > > > > + /* VMI may relocate the fixmap; do this before touching ioremap area */ > > + vmi_init(); > > + > > early_cpu_init(); > > early_ioremap_init(); > > > > @@ -880,13 +883,8 @@ void __init setup_arch(char **cmdline_p) > > check_efer(); > > #endif > > > > -#if defined(CONFIG_VMI) && defined(CONFIG_X86_32) > > - /* > > - * Must be before kernel pagetables are setup > > - * or fixmap area is touched. > > - */ > > - vmi_init(); > > -#endif > > + /* Must be before kernel pagetables are setup */ > > + vmi_activate(); > > > > /* after early param, so could get panic from serial */ > > reserve_early_setup_data(); > > > > > > and according to > > http://lkml.org/lkml/2008/12/10/388 > > http://lkml.org/lkml/2008/12/10/456 > > > > Zachary should split reserve_top_address() to two functions... > > before sending that patch to Linus > > mind looking at this yourself if interested? Zachary has not been > active for quite some time. > > Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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